Molecular Biology Commons^™

Glutathionylation/Glutaredoxin Axis And The Regulation Of Epithelial Cell Plasticity And Fibroblast Activation In Airway Fibrosis, Shi Biao Chia

Graduate College Dissertations and Theses

Asthma is a complex lung disorder that affects more than 200 million people across the globe. About 10% of asthmatics have severe disease accompanied by structural airway remodeling, including subepithelial fibrosis, airway smooth muscle cell hyperplasia, goblet metaplasia, and increased vascularization. Oxidative stress has been well-linked to asthma pathogenesis; however, the precise redox mechanisms governing the pathological states are slowly being teased apart in the recent years. Protein S-glutathionylation (PSSG) is a posttranslational modification where a three amino acid-peptide, glutathione, forms a disulfide bond with reactive cysteines of a protein thereby potentially changing the protein’s biological functions. Glutaredoxins are members …

Molecular Mechanisms Of Mrna Transport By A Class V Myosin And Cytoplasmic Dynein, Thomas Edward Sladewski

Graduate College Dissertations and Theses

mRNA localization ensures correct spatial and temporal control of protein synthesis in the cell. Using a single molecule in vitro approach, we provide insight into the mechanisms by which localizing mRNAs are carried by molecular motors on cytoskeletal tracks to their destination.

Budding yeast serves as a model system for studying the mechanisms of mRNA transport because localizing mRNAs are moved on actin tracks in the cell by a single class V myosin motor, Myo4p. Molecular motors that specialize in cargo transport are generally double-headed so that they can "walk" for many microns without dissociating, a feature known as processivity. …

Functional And Mechanistic Consequences Of Dual Oxidase 1 Suppression In Lung Cancer, Andrew Charles Little

Graduate College Dissertations and Theses

The NADPH oxidase homolog, dual oxidase 1 (DUOX1), is an H2O2 producing transmembrane enzyme highly expressed in the airway epithelium. DUOX1-dependent redox signaling has been characterized to regulate many homeostatic processes in the lung epithelium, such as host defense, wound healing, and type II immune responses. Intriguingly, DUOX1 has been found to be suppressed in many epithelial cancers, including lung cancer, by hypermethylation of its promoter. Epigenetic silencing of DUOX1 in cancer is paradoxical to the understanding that tumors harbor elevated levels of reactive oxygen species (ROS), suggesting that DUOX1 may be a tumor suppressor.

Since DUOX1 loss occurs in …

Mechanisms And Dynamics Of Oxidative Dna Damage Repair In Nucleosomes, Wendy J. Cannan

Graduate College Dissertations and Theses

DNA provides the blueprint for cell function and growth, as well as ensuring continuity from one cell generation to the next. In order to compact, protect, and regulate this vital information, DNA is packaged by histone proteins into nucleosomes, which are the fundamental subunits of chromatin. Reactive oxygen species, generated by both endogenous and exogenous agents, can react with DNA, altering base chemistry and generating DNA strand breaks. Left unrepaired, these oxidation products can result in mutations and/or cell death. The Base Excision Repair (BER) pathway exists to deal with damaged bases and single-stranded DNA breaks. However, the packaging of …

Dna Glycosylases Remove Oxidized Base Damages From G-Quadruplex Dna Structures, Jia Zhou

Graduate College Dissertations and Theses

The G-quadruplex DNA is a four-stranded DNA structure that is highly susceptible to oxidation due to its G-rich sequence and its structure. Oxidative DNA base damages can be mutagenic or lethal to cells if they are left unrepaired. The base excision repair (BER) pathway is the predominant pathway for repair of oxidized DNA bases. DNA glycosylases are the first enzymes in BER and are responsible for removing base lesions from DNA. How DNA glycosylases remove base lesions from duplex and single-stranded DNA has been intensively studied, while how they act on G-quadruplex DNA remains to be explored.

In Chapter II …

Helicase-Ssb Interactions In Recombination-Dependent Dna Repair And Replication, Christian Jordan

Graduate College Dissertations and Theses

Dda, one of three helicases encoded by bacteriophage T4, has been well- characterized biochemically but its biological role remains unclear. It is thought to be involved in origin-dependent replication, recombination-dependent replication, anti- recombination, recombination repair, as well as in replication fork progression past template-bound nucleosomes and RNA polymerase. One of the proteins that most strongly interacts with Dda, Gp32, is the only single-stranded DNA binding protein (SSB) encoded by T4, is essential for DNA replication, recombination, and repair.

Previous studies have shown that Gp32 is essential for Dda stimulation of replication fork progression. Our studies show that interactions between Dda …

Regulation Of Β-Casein Gene Expression By Octamer Transcription Factors And Utilization Of Β-Casein Gene Promoter To Produce Recombinant Human Proinsulin In The Transgenic Milk, Xi Qian

Graduate College Dissertations and Theses

β-Casein is a major milk protein, which is synthesized in mammary alveolar secretory epithelial cells (MECs) upon the stimulation of lactogenic hormones, mainly prolactin and glucocorticoids (HP). Previous studies revealed that the proximal promoter (-258 bp to +7 bp) of the β-casein gene is sufficient for induction of the promoter activity by HP. This proximal region contains the binding sites for the signal transducer and activator of transcription 5 (STAT5), glucocorticoid receptor (GR), and octamer transcription factors (Oct). STAT5 and GR are essential downstream mediators of prolactin and glucocorticoid signaling, respectively. This study investigated the functions of Oct-1 and Oct-2 …